1. Field of the Invention
This invention relates to a vehicle anti-freeze monitor for monitoring the capability of the vehicle's coolant mixture in the cooling system of the vehicle to resist freezing.
2. Information Disclosure Statement
A preliminary patentability search in Class 340, subclass 624 revealed the following patents: Brown et al, U.S. Pat. No. 3,777,574; Uemura et al, U.S. Pat. No. 3,947,813; Hilblom, U.S. Pat. No. 3,954,010; Spencer, U.S. Pat. No. 4,003,255; Nakagawa, U.S. Pat. No. 4,020,481; Nagara et al, U.S. Pat. No. 4,107,493; Patis, U.S. Pat. No. 4,350,885; Guay et al, U.S. Pat. No. 4,400,978; Okada et al, U.S. Pat. No. 4,833,441 and Budecker et at, U.S. Pat. No. 4,843,193.
The Brown et al patent discloses a specific gravity sensor of the type in which a beam of light is interrupted by a light-flow inhibitor which lowers in liquid when the specific gravity of the liquid decreases.
The Uemura et al patent discloses a liquid level reduction alarm device for a liquid reservoir vessel kept in liquid communication with a brake master cylinder for delivery of an alarm signal to the vehicle driver if the liquid level in the reservoir vessel should reduce to an excessive degree so as to warn the driver to replenish the brake oil.
The Hilblom patent discloses a combined visual and electronic liquid indicator which may be used as a battery hydrometer, which also operates on the principle of either a visual indication of the specific gravity or an electronic indication by the use of a float ball as a shutter between the light source and the light detector.
The Spencer patent is a method and apparatus for measuring fluid flow and controlling fluid flow systems by the use of a magnetically responsive float. Also the system can be employed to determine fluid viscosity.
The Nakagawa patent discloses a fluid level alarm device for use with automotive vehicles for informing the operator of the vehicle of a reduction below a certain level of an operating fluid stored in the fluid tank associated with a master cylinder to serve the purpose of preventing any resultant failure in operation of the master cylinder. The alarm device operates by positioning a magnetically operable reed switch, electrically connected to an alarm, so when the fluid stored in the tank is lowered below a specified level, the reed switch is magnetically closed to operate the alarm.
The nagara et al patent discloses a radiator cap which includes a float engaged with the cap body so as to move up and down in accordance with the level of the coolant. A reed switch secured to the cap body is opened or closed in response to movement of the float so that the reed switch actuates suitable warning means when the liquid level is too low.
The Patis patent discloses a battery hydrometer which provides an analog output electrical signal related to the specific gravity of the battery electrolyte.
The Guay et al patent discloses an electronic hydrometer having an electronic circuit capable of automatically controlling the position of a float by means of a variable current supply and providing an output signal indicative of the density of the liquid.
The Okada et al patent discloses a reservoir for the coolant of the radiator of a automobile and includes a reed switch for warning that the level of liquid contained in the reservoir is below a prescribed level. A float is included having a magnet to close the reed switch.
The Budecker et al patent discloses a reservoir for a hydraulic brake system provided with a screw coupling and a reservoir telltale sounding device.
In addition, it should be pointed out that the determination of an automobile's anti-freeze protection has thus far remained a somewhat laborious process of manually opening into the cooling system, extracting a sample of coolant fluid, and inspecting a visual hydrometer. This hydrometer usually consists of floating elastomeric balls which are calibrated to float at various densities of coolant fluid, thus providing a visual measurement of the freezing point of the solution. Today's automobiles generally run considerably hotter than formerly and require some method to provide for the resulting expansion of the coolant liquid. An overflow tank is now commonly used. It collects the coolant as it expands out of the radiator in its superheated phase and provides an escape mechanism whereby the fluid may subsequently be withdrawn back into the cooling system as the engine cools down. Gaining access to the coolant liquid by manual extraction is laborious and sometimes dangerous.
A variety of electronic hydrometers for measuring the specific gravity of electrolytes with opto-isolation techniques is well known in the art. The difficulties of constructing light emitting and light detecting circuitry with complex housing and lenses have thus far failed to satisfy the need of a simple device suitable for placement within an automobile coolant system.
None of the above mentioned prior art discloses or suggests the present invention. More specifically, none discloses or suggests a vehicle anti-freeze monitor for monitoring the capability of the vehicle's coolant mixture in the cooling system of the vehicle to resist freezing, comprising: indicator means; switch means movable between first and second positions for respectively selectively activating and deactivating said indicator means; and means for submersion in the vehicle's coolant mixture for moving said switch means to said first position when the specific gravity of the vehicle's coolant mixture is greater than a selected certain specific gravity corresponding to the lowest temperature point of a base coolant mixture above which the base coolant mixture is considered to be safe a to its capability of resisting freezing to activate said indicator means, and for moving said switch means to said second position when the specific gravity of the vehicle's coolant mixture is below said selected certain specific gravity to deactivate said indicator means.